1. Field of the Invention
The present invention relates generally to endoscopic surgical methods and apparatus. More particularly, the present invention provides an access catheter having a distally protruding structure which maintains separation between a viewing scope and a lumenal wall.
Diseases of the fallopian tubes are a major cause of infertility and tubal pregnancy. Until recently, diagnosis and treatment of tubal disease has been hampered by the difficulty in accessing and imaging the interior of the fallopian tube. Such difficulties, however, have been largely overcome by the recent availability of very small guidewires, catheters, and fiberoptic viewing scopes, usually referred to as falloposcopes. Using these instruments and systems, a physician can gain atraumatic access to the interior of the fallopian tube through a hysteroscope positioned within the uterus. Such falloposcopic imaging techniques were described by Kerin et al. in Fertil. Steril., Vol. 54, pp. 390-400 (1990), and in J. Laparoendoscopic Surg., Vol. 1, pp. 47-56.
Falloposcopic access and imaging techniques are generally performed as follows. A hysteroscope is positioned within the uterus and an irrigating solution is introduced to distend the uterus and permit video monitoring. A very small guidewire is then introduced through the hysteroscope and advanced past the ostium and into the fallopian tube. The guidewire will continue to be advanced until it approaches the distal fimbria. A small tubular access catheter may then be advanced through the hysteroscope and over the guidewire into the fallopian tube, again preferably approaching the distal fimbria. After removing the guidewire, the falloposcope (which is a small diameter fiberoptic bundling including both imaging and illumination fibers in a single shaft) is advanced until its distal end reaches the distal end of the access catheter. Imaging may then be performed in a retrograde manner with the falloposcope and access catheter being drawn outwardly together through the fallopian tube while producing an image on the associated video monitor. The lumen of the tubular access catheter will also provide an access path for devices, such as drug delivery catheters, small instruments, and the like, for treatment of tubal lumen disease.
While such retrograde falloposcopic imaging techniques represent a significant improvement, they still suffer from certain limitations. In particular, falloposcopes having both illumination and imaging fiberoptics require a minimum separation between the imaging lens at the end of the fiberoptic bundles and the tissue to be imaged. Unfortunately, the narrowly confined lumen of the fallopian tube contracts soon after the access catheter has been withdrawn. Hence, the tubal wall often collapses in on the withdrawing falloposcope during retrograde imaging, intruding upon the required imaging separation. As the tubal wall tissues come in close proximity with the imaging and illumination fiberoptics, excessive illumination light is reflected back to the imaging system, causing a partial or total "white-out" of the viewing monitor. These white-outs are a common and undesirable limitation on the effectiveness of retrograde imaging of the fallopian tube and other narrow body lumens.
It would therefore be desirable to provide improved methods and systems for imaging fallopian tubes and other narrow body lumens. It would be particularly desirable to provide improved access catheters and methods for their use which would reduce the incidence of white-out associated with the fallopian tubal wall approaching too close to the optical viewing scope. It would further be desirable if such improved methods and devices were compatible with and able to enhance the effectiveness of retrograde tubal imaging systems and methods.
2. Description of the Background Art
Kerin et al., Fertil. Steril., Vol. 54, pp. 390-400 (1990), and in J. Laparoendoscopic Surg., Vol. 1, pp. 47-56, have been described above. U.S. Pat. No. 4,793,326 describes an industrial endoscope having an elongated arm member to facilitate advancing separate illumination and observation windows past the abrupt steps of piping elbow joints. U.S. Pat. No. 4,717,387 describes an intercardiac catheter having a distal balloon for positioning the catheter with respect to a body surface to be viewed through an optical scope. U.S. Pat. No. 5,263,982 describes an endoscopic catheter having a laterally offset movable guidewire.
U.S. Pat. Nos. 5,047,848 and 4,825,259 disclose borescope having specialized distal tip gauges which permit optical measurements of imaged features. U.S. Pat. No. 4,608,965 discloses an endoscopic sheath having a Malecott-type structure for anchoring the scope in a body cavity.
U.S. Pat. No. 5,358,496 is representative of numerous instruments intended to be inserted through endoscopes. U.S. Pat. Nos. 3,866,601; 4,306,566; 4,350,147; 4,846,812; 5,099,827; 5,263,928; 5,279,596; 5,306,261; 5,307,814; 5,308,342; 5,385,152; are also relevant.
An exemplary falloposcopic imaging system is described in copending application Ser. No. 08/027,475, the full disclosure of which is incorporated herein by reference.